2014-01-25 17:15:09

by Jean-Francois Moine

Subject: [PATCH v4 24/24] drm/i2c: tda998x: adjust the audio clock divider for S/PDIF

According to some tests on the Cubox (Marvell Armada 510 + TDA19988),
the S/PDIF input asks for a greater audio clock divider.

Signed-off-by: Jean-Francois Moine <[email protected]>
---
drivers/gpu/drm/i2c/tda998x_drv.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i2c/tda998x_drv.c b/drivers/gpu/drm/i2c/tda998x_drv.c
index b4827c0..e4dfcb4 100644
--- a/drivers/gpu/drm/i2c/tda998x_drv.c
+++ b/drivers/gpu/drm/i2c/tda998x_drv.c
@@ -679,10 +679,14 @@ tda998x_configure_audio(struct tda998x_priv *priv,
* There is no detailed info in the datasheet, so we just
* assume 100MHz requires larger divider.
*/
+ adiv = AUDIO_DIV_SERCLK_8;
if (mode->clock > 100000)
- adiv = AUDIO_DIV_SERCLK_16;
- else
- adiv = AUDIO_DIV_SERCLK_8;
+ adiv++; /* AUDIO_DIV_SERCLK_8 */
+
+ /* S/PDIF asks for a larger divider */
+ if (p->audio_format == AFMT_SPDIF)
+ adiv++; /* AUDIO_DIV_SERCLK_16 or _32 */
+
reg_write(priv, REG_AUDIO_DIV, adiv);

/*
--
1.8.5.3

2014-01-27 20:12:40

by Russell King - ARM Linux

Subject: Re: [PATCH v4 24/24] drm/i2c: tda998x: adjust the audio clock divider for S/PDIF

On Sat, Jan 25, 2014 at 06:14:36PM +0100, Jean-Francois Moine wrote:
> According to some tests on the Cubox (Marvell Armada 510 + TDA19988),
> the S/PDIF input asks for a greater audio clock divider.
>
> Signed-off-by: Jean-Francois Moine <[email protected]>
> ---
> drivers/gpu/drm/i2c/tda998x_drv.c | 10 +++++++---
> 1 file changed, 7 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/i2c/tda998x_drv.c b/drivers/gpu/drm/i2c/tda998x_drv.c
> index b4827c0..e4dfcb4 100644
> --- a/drivers/gpu/drm/i2c/tda998x_drv.c
> +++ b/drivers/gpu/drm/i2c/tda998x_drv.c
> @@ -679,10 +679,14 @@ tda998x_configure_audio(struct tda998x_priv *priv,
> * There is no detailed info in the datasheet, so we just
> * assume 100MHz requires larger divider.
> */
> + adiv = AUDIO_DIV_SERCLK_8;
> if (mode->clock > 100000)
> - adiv = AUDIO_DIV_SERCLK_16;
> - else
> - adiv = AUDIO_DIV_SERCLK_8;
> + adiv++; /* AUDIO_DIV_SERCLK_8 */
> +
> + /* S/PDIF asks for a larger divider */
> + if (p->audio_format == AFMT_SPDIF)
> + adiv++; /* AUDIO_DIV_SERCLK_16 or _32 */

I'm not sure these comments are quite right... You start off with
adiv at AUDIO_DIV_SERCLK_8, and then you increment it, but the
comment says it's AUDIO_DIV_SERCLK_8 ? Shouldn't it become
AUDIO_DIV_SERCLK_16 ?

Please review the above change yourself. :)

--
FTTC broadband for 0.8mile line: 5.8Mbps down 500kbps up. Estimation
in database were 13.1 to 19Mbit for a good line, about 7.5+ for a bad.
Estimate before purchase was "up to 13.2Mbit".